JPS6212745A - Conversion of primary alkanol to corresponding ester - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD This invention relates generally to the conversion of primary alkanols to the corresponding alkanoate esters. More particularly, the present invention relates to the conversion of anhydrous or aqueous alkanols having C to about C15 carbon chains to the corresponding alkanoate esters.

BACKGROUND OF THE INVENTION Commercial production of esters has traditionally required a two-step process. The process involves oxidizing an alcohol to an acid and then reacting the acid with another alcohol.
The esters formed can have many commercial uses. Low molecular weight esters are useful as solvents. Low molecular weight esters can also be used as intermediates to produce the corresponding acids, such as acetic acid. The higher molecular weight esters can be used as lubricants or as intermediates in the production of nidistomers and synthetic fibers.
The fact that esters are useful directly or indirectly in commercial products has sparked interest in ways to develop esters at low cost. The development of these processes has focused on methods that either reduce the number of steps to produce the ester, reduce the cost of the reactants or catalysts used in the process, or increase the overall ester yield of the process. Was. The following patents are examples of methods developed for ester production.

U.S. Pat. No. 4,052,424 to Vanderspurt discloses a process for making esters from alkanols. This process involves contacting a gaseous alkanol with a silver-cadmium alloy catalyst to achieve high yields of ester. In this process, alkanols are vaporized either alone or in admixture with nitrogen, hydrogen, carbon oxides or carbon dioxide.

Steam is passed into a reaction zone containing a silver-cadmium alloy catalyst. The catalyst can be fixed bed, moving bed or fluidized bed.

The temperature of the reaction zone is about 135 to about 600°C.

The pressure in the reaction zone is about 5 to about 2 oopsia (about 135 to about
(approximately 140 kg/crn2A). A mixture of gas and alkanol vapor is used to control undesirable side reactions.

U.S. Patent No. 3 related to Kunugl et al.
, 659.449 discloses a process for making esters of carboxylic acids. The method involves reacting at least one alcohol in a mixture of at least one alcohol and at least one aldehyde with molecular oxygen in the presence of a catalyst. Catalyst has atomic number 44-7
8 of the periodic table, oxides of these metals, pretreated products of these metals, and pretreated products of these metal oxides, provided that the alcohol alone is reacted with molecular oxygen. If so, it is provided that at least one primary alcohol is present in the alcohol. The process disclosed in this patent uses a palladium chloride catalyst and produces hydrogen gas chloride after completion of the reaction. Reduced palladium is produced from the system and catalyst regeneration is required.

Regeneration is done with copper chloride or acetic acid steel to oxidize the catalyst back to palladium chloride.

U.S. Patent No. 3,452,06 related to pine
No. 7 discloses a method for producing esters from alcohols. This process produces esters by catalytic dehydrogenation and disproportionation of alcohols in the gas phase in the presence of molybdenum sulfide catalysts. The resulting ester contains twice as many carbon atoms as the original alcohol. The reaction is carried out on a supported catalyst at 400
The process of this patent uses aliphatic, saturated, primary alcohols containing from 2 to about 15 carbon atoms. Mixtures of can be used to obtain esters with varying carbon chain lengths extending from the ester functionality on the two sides.Catalyst carriers include various alumina and silicon materials.

US Patent No. λ related to Lazier
No. 079.414 discloses a process for producing alcohols from esters of non-aromatic carboxylic acids. In this patent, esters of non-aromatic carboxylic acids are prepared with hydrogen gas at 25
Process at temperatures above 0°C and overpressure. This reaction is carried out in the presence of a hydrogenation catalyst. The catalyst is considered to be a single hydride metal or its oxide or a mixture of hydride metals and their oxides. Examples of catalysts include those containing nitrate steel, oxidized steel, copper chromite, and the like.

Many of the processes used in industry to produce esters from alkanols, particularly ethanol, require essentially pure alkanol feed solutions.

In the process of converting ethanol, commercial grade
:190 proof ethanol is not suitable as an alkanoic feed solution. This is Al
5X water concentration in l canol feed solution produces varnish
This is because it reduces chill productivity. water-based alkaline
Processes that cannot use iCalls
.

The supplied alcohol is 200 proof ethanol.
It needs to be dried to . Pure ethanol is lighter than commercially available 190 proof ethanol.
;can cost between 5 and 20 cents per bottle. beauty salon
□In large-scale production of varnish, this price difference is
□ Can have a significant impact on chill prices.

The problem to be solved by the invention is that the reaction has a high selectivity conversion to the desired ester and produces less by-products such as acids, aldehydes, higher alcohols, gaseous derivatives, etc. There is a need for a method for producing esters from primary alcanols.

In addition, the industry lacks a method that can effectively use aqueous alkanol feed solutions.

DISCLOSURE OF THE INVENTION SUMMARY OF THE INVENTION The present invention includes a process for making an alkanoate ester comprising contacting a gaseous primary alkanol with a copper-containing catalyst in a reactor. The invention further includes adjusting the molar ratio of hydrogen gas to warm alkanol within the reactor.

the molar ratio is substantially controlled by means of controlling the reaction equilibrium between the primary alkanol and the aldehyde intermediate compound;
This partially suppresses the formation of aldehydes and increases the selectivity of aldehydes to alkanoate ester reaction products.

The present invention collects the alkanoate ester, water, and alkanol by means of azeotropic distillation of the reactor effluent;
The method may then include separating.

If the process of the invention includes an azeotropic distillation step, the anhydrous alkanol that is separated can optionally be recycled as an alkanol feed solution. Distilled alkanol can be mixed into the aqueous alkanol feed solution without significantly reducing productivity or efficiency of alkanoate ester production.

DETAILED DESCRIPTION The present invention is a process for preparing alkanoate esters from primary alkanol compounds. The method contacts a gaseous primary alkanol with a copper-containing, more preferably copper chromite-containing catalyst in a reactor. The molar ratio of hydrogen gas to alkanol feed solution in the reactor is selectively adjusted to optimize the reaction equilibrium that favors alkanoate ester production and suppresses the formation of undesirable by-products. Adjusting the molar ratio of hydrogen gas can be accomplished by means of controlling hydrogen gas flow rate, reactor temperature, reactor pressure, or a combination thereof. The hydrogen gas flow rate, reactor temperature, and reactor pressure are controlled to drive the reaction equilibrium toward high productivity and high efficiency of the desired alkanoate ester production. The reaction product containing the alkanoate ester formed is then discharged from the reactor. The alkanoate ester can be further purified by azeotropic distillation means. When using an azeotropic distillation process, the anhydrous alkanol can be recycled to the reactor as the alkanol feed solution.

An effective, commercially practical and straightforward method of converting anhydrous or aqueous alkanols having carbon chains of C1 to C15 or more to their corresponding esters involves the following chemical process steps. The first reaction that occurs in the presence of a copper-containing catalyst is rapidly established between an alkanol and its aldehyde.

Equilibrium: m R, CH20H'=:p RlCI-I + R
2, where R1 is a member selected from the group consisting of hydrogen or an alkyl group of up to 14 carbon atoms.

´° This reaction is governed by the following equilibrium constant: ■ The second reaction that occurs is the equilibrium formation of a hemiacetal from an alkanol and an aldehyde: The main rate-limiting step in the reaction converting an alkanol to its corresponding ester is , the reaction of hemiacetals to alkanoate esters. This reaction results in an equilibrium state that is highly favorable for the formation of esters: (net) 2R1CI-(20H←1,000R, CH20CR
,+2H2.

From this series of reactions, it is assumed that the rate of ester production depends on the concentration of hemiacetal: ester production rate = x [hemiacetal].

The production rate of hemiacetal is different from that of aldehyde and burka.
□Depends on the concentration of both: Hemiacetal formation rate = x [aldehyde] [alkanol]. □
The formation of an alkanol to its corresponding ester is linearly related to the concentration of the aldehyde intermediate compound.

The most significant by-product in alkanol conversion reactions using steel-containing catalysts is due to the condensation of aldehyde intermediate compounds. The aldehyde intermediate compound is in equilibrium with its corresponding aldol: The aldol compound is in equilibrium with the unsaturated alcohol and water: R1R1 The unsaturated alcohol irreversibly forms a branched aldehyde in the presence of hydrogen gas: R1R .

The net by-product equation is: The formation of an aldehyde to its by-product is quadratic with the square of the concentration of the aldehyde compound. Therefore, the efficiency selectivity of an alkanol conversion unit with a copper-containing catalyst depends significantly on the average concentration of aldehyde within the reaction zone. This is because aldehyde by-products are influenced in part by aldehyde concentration more than the corresponding ester formation. Increasing the aldehyde concentration within the reactor zone does not significantly change the concentration of ester produced when a copper-containing catalyst is present. When zinc is present in the catalyst, ester production from alkanols depends on the concentration of aldehyde in the reactor zone.

The method of the present invention has the unexpected result of increasing the concentration of ester in the alkanol conversion reaction by controlling and increasing the presence of hydrogen gas within the reaction zone.

This result is unexpected for two reasons.

The first reason why the results of the process of the invention are unexpected is that the addition of hydrogen gas suppresses or partially suppresses the formation of the aldehyde intermediate compound of reaction formula (1). The formation of aldehyde intermediate compounds is inhibited in part by increasing the concentration of hydrogen gas because the interrelationship of these two compounds is as expressed by their equilibrium constants. An aldehyde intermediate compound is required for the formation of the corresponding ester. Suppressing aldehyde intermediate compounds by adjusting the concentration of hydrogen gas reduces the availability of aldehydes for by-product formation, thereby increasing the selectivity of aldehydes to the corresponding ester formation.

A second reason why the results of the process of the invention are unexpected is that hydrogenation of esters to the corresponding alcohols is a well known process. The presence of increased concentrations of hydrogen gas may be expected to inhibit ester formation in reaction equation (3). Adjusting the presence of hydrogen gas in the reactor zone in accordance with the present invention results in K
Therefore, the generation of ℃2 stell is enhanced. Exceeding the concentration of hydrogen gas in the reactor zone to an extent that adjusts the reaction equilibrium between the primary alkanol and the aldehyde intermediate compound reduces the formation of the corresponding ester compound.

Adjusting the molar ratio of hydrogen gas to hot-alkanol in the reactor, i.e., the reactor zone, is achieved by adjusting the hydrogen gas flow rate,
This can be accomplished by a number of means of controlling reactor temperature, reactor pressure, or a combination thereof. Regulation of hydrogen gas within the reactor can be accomplished by circulating hydrogen gas from an exogenous source or, more preferably, separated from the reaction products. The molar ratio of hydrogen gas to warm alkanol is also adjusted by feeding aldenyhyde to the reactor. ．． ．． 0°
! 1: As can be observed from the above equation, the increase in temperature is i
It has the property of increasing the equilibrium constant. a reaction occurs
The increase in pressure at the point of
The relative amount of aldehyde produced is reduced. Then,
An increase in the hydrogen gas concentration will sacrifice the aldehyde concentration. picture,. 4. 8a 1:)'<7)II
The I degree was found to be dependent on the reaction rate but controlled by the equilibrium of the reaction to further react with the alkanol to produce the desired alkanoate ester. By adjusting the hydrogen gas concentration within the reactor, the concentration of aldehyde present during the reaction is controlled. Adjusting the molar ratio of hydrogen gas to alkanol feed solution in the reactor in accordance with the present invention partially suppresses the formation of aldehyde intermediate compounds and increases the selectivity of aldehydes to alkanoate ester reaction product formation.

The major inefficiency encountered with the reaction of converting primary alkanols to the corresponding esters is the formation of aldehyde condensation products. For example, the condensation products of acetaldehyde in the process of ethanol to ethyl acetate are crotonaldehyde, butyraldehyde, and butanol. Crotonaldehyde is produced by dehydration of acetaldol (a dimer of acetaldehyde). The rate of crotonaldehyde production depends on the square of the acetaldehyde concentration. The rate of ethyl acetate ester formation is linearly dependent on the acetaldehyde concentration.

The production efficiency of alkanoate esters is directly related to the degree of aldehyde concentration and directly dependent on the aldehyde concentration within the reaction zone. As can be seen from these relationships, a reaction method that adjusts the molar ratio of hydrogen gas to alkanol feed solution moles in the reaction zone will result in high alkanoate ester production. By controlling the molar ratio of hydrogen gas to alkanol feed solution by adjusting the hydrogen gas feed rate, reactor temperature, and reactor pressure, the conversion reaction of alkanol to the corresponding alkanoate ester can be selectively controlled and It becomes possible to optimize.

Adjustment of the molar ratio of hydrogen gas to alkanol feed solution in the reaction zone must be sufficient to suppress the aldehyde concentration. Preferably, the molar ratio of hydrogen gas to alkanol feed solution in the reaction zone is such that the concentration of aldehyde is reduced enough to increase the efficiency of ester production.

The molar ratio of hydrogen gas should not be so high as to substantially suppress the formation of aldehyde intermediate compounds. Too high a concentration of hydrogen gas in the reaction zone can overwhelm the presence of aldehydes and adversely affect the conversion of alkanols to alkanoate esters as described above.

Suppressing the concentration of aldehyde present within the reaction zone increases reaction efficiency, but reduces the overall production of alkanoate ester. The most preferred molar ratio of hydrogen gas to alkanol feed solution in the reaction zone is about 0.6 hydrogen gas.
~5 moles to 1 mole of alkanol feed solution. The desired molar ratio of hydrogen gas to alkanol feed solution moles is:
Approximately 4 to 5 L of hydrogen gas to 1 L of alkanol feed solution
It is a mole. A molar ratio of hydrogen gas to alkanol feed solution with trace amounts of hydrogen gas, such as from about 5 moles or less to about 12 moles of hydrogen gas per mole of alkanol feed solution, is effective. Above about 12 moles of hydrogen gas, suppression of ester formation begins to impair the conversion reaction.

The method of the present invention is a gas phase process and can employ one of many commercially available copper-containing catalysts. The most preferred embodiment of the invention employs a copper chromite containing catalyst. The process of the present invention employs these catalysts at reactor temperatures of about 200° to about 300°C and reactor pressures of about 0 to about 500°C.
psig (about 0 to about 35 kg/cm2G). A more preferred temperature and pressure range is from about 220° to about 260° respectively.
°C and about 10 to about 100' psig (about 0.7 to about 7
kg/c1! t2G). Most preferred reactor pressures are about 30 to about 80 psig (about 2.1 to about 5.6 psig).
kli/cm”G). Approximately 300° to approximately 3
Above 50°C, adding increased hydrogen gas to the reactor increases the efficiency of ester production, but also increases by-product formation. The molar ratio of hydrogen gas to alkanol feed solution required to increase ester production can vary depending on reactor temperature. An increase in the reactor temperature increases the hourly amount of hydrogen gas required to increase the ester efficiency.
Requires a natural increase.

The process of the present invention provides high alkanol conversions, typically from about 20 to about 75X'. The production of alkanoate esters when carried out by the method of the present invention results in efficiencies of about 80 to about 100 yX.

The process has a comparable productivity of about 10 to about 50 pounds per ft' hour of catalyst. In addition to high conversion efficiency and productivity, the process produces large amounts of useful high quality hydrogen gas that can be used in other chemical processes.

The copper chromite-containing catalyst used in the process of the invention can work for long periods of time. These catalysts can be regenerated and are cheaper than specialty metal catalysts. Long operating periods for copper chromite catalysts used in alkanol conversion reactions can exceed 6,000 to 8,000 hours of operation per year and can be used for four years or more. The 8000 hour operating period equates to approximately one year of typical commercial use of the catalyst. The long operating times of copper chromite-containing catalysts are due to the resistance of copper chromite to -S, the organic acids inherent in the process.

When organic acids come into contact with certain catalysts, especially those containing zinc, the catalysts can be decomposed. Prolonged use of the catalyst to carry out this reaction can cause an increase in carbon deposits within the catalyst. This leads to loss of activity of the catalyst. The copper chromite-containing catalyst can be regenerated by stopping the supply of hydrogen gas and alkanol feed solution to the reactor and supplying air into the reactor. The air burns off the carbon deposits and restores the activity of the catalyst to its original level. The recyclability of copper chromite is desirable when compared to catalysts whose deactivation due to carbon deposition is irreversible. The copper chromite catalyst is typically regenerated 5 to 6 times per year and about 20 total times during the operating life of the Yoshi catalyst without loss of activity.

The cost of Nitrous Chronic catalyst is less than some other catalysts, catalysts containing % silver.

Copper chromite catalysts suitable for use in the present invention are Ohai No. 44106, Creepland, 1945 E.S.) No. 9
-7 Street, Barshaw/Filtrow K (H
Arshaw/Fitrol) Company. The copper chromite catalyst used in the most preferred embodiment of the present invention is a copper chromite catalyst provided by this source and designated Versho Cu-0203. Catalysts with K, other copper chromite catalysts and mixtures of copper with other substances such as alumina can be obtained and used in the present invention. The specific example desired is 170 Kaskel Avenue, Ely, Pennsylvania 1650B.
E-18TU Catalyst from Mallinckrodt Corporation, Calcicat Division, 7,000, and G-13 from Enitated Catalysts Corporation, P.O. Box 32370, Louisville, 40232 Kentucky.
or G-22 catalyst. The process of the present invention is not limited to particular copper-containing catalysts or to particular copper chromite-containing catalysts.

Suitable catalysts may contain other catalytic metals such as barium. The efficiency of the reaction in the process of the invention is independent of the catalyst, but depends on the molar ratio of hydrogen gas to alkanol feed solution in the reaction zone. It is the control of the reaction equilibrium, not the catalyst, that increases the efficiency of the reaction of the present process. Specific examples of steel-containing catalysts are: Non-barium-containing catalysts Cu-0203 Cu-1422 Cu-1808 Cu-1809 Barium oxide-containing catalysts Barium oxide Cu-H
O77X Cu-11178X Cu-0329% Cu-11849X Cu-11869X Cu 2501G410 (Granyl)
Silica & C5X+7) CuE-103TU E-105 E-18'l'U E-403TU Barium oxide-containing catalyst Barium E-1013
-7% E-102
3-7 XE-10+STU
8%E-406TU
8%G-89 Manganese 3%C
u 39% Chromium 37% (non-metallic oxide) Barium oxide containing catalyst G-22 Barium 10-11 The desired product can be isolated and purified by distillation.

The reaction products in the effluent are alkanoate ester, water,
Contains anhydrous alkanol and other by-products produced during the reaction. The separated anhydrous alkanol can be recycled to the alkanol feed solution to the reactor. The process according to the invention allows the anhydrous alkanol to be used productively as an alkanol feed solution by circulating the separated anhydrous alkanol. For example, in the conversion of ethanol to ethanoate ester or ethyl acetate, commercial grade 190 proof (95ii
%) ethanol can be used as the alkanol feed solution. Using 190 proof ethanol as the feed solution typically requires starting the reaction with 200 proof ethanol. The reaction products must be produced in sufficient concentrations to initiate azeotropic distillation. Absolute ethanol was then circulated and 1
Mix into 90 proof ethanol feed solution.

Producing enough distilled anhydrous alkanol to make aqueous or 190
A 1:1 mixture with proof ethanol can be formed. The mixture has an effective concentration of about 2.5% water.

Continuous distillation and circulation of absolute ethanol allows 190 proof ethanol to be used alone as the feed solution in the process after initiation of the reaction.

The productivity of conversion of alkanol to alkanoate ester depends on the water content of the alkanol feed solution. By increasing the reaction temperature and maintaining a sufficient molar ratio of hydrogen gas to balance the reaction of the present invention, some of the productivity losses due to the presence of water in the alkanol feed solution are recovered. can do. Although the productivity loss due to water in the alkanol feed solution is still evident when compared to the results obtained with pure alkanol feed solutions, the level of ester production obtained is commercially acceptable. This may be due to the price difference between (11) aqueous alkanol feed solution and pure alkanol feed solution, or (2)
This is because the cost of drying the aqueous alkanol feed solution is greater than the economic loss suffered by the low productivity of the alkanoate ester.

Fermented ethanol feed solutions can also be used in the method of the invention. The fermentation ethanol feed solution is less pure than commercial grade 190 proof ethanol. Higher water concentrations in the fermentation ethanol feed solution reduce the productivity of the reaction of the process. The method provides further commercial applications for fermented ethanol.

An industrial scale unit suitable for carrying out the method of the invention can be further understood by reference to FIG. The alkanol supply tank 1 or the supply source supplies the alkanol supply solution to the reactor 2 from the pipeline □10.
supply to. The reaction product or effluent leaves the reactor 2 via line 11 and enters the hydrogen gas separator? t3Vc enters. Hydrogen gas is extracted from the yarn, transported through the hydrogen gas line 12, and recirculated through the supply line 101C through the line 23 l' and means 1 for circulating hydrogen gas, such as the hydrogen compressor 9. is hydrogen □Transported to gas collector 4. The recirculated hydrogen gas is supplied to the reactor 2 using various suitable means for controlling or regulating the recirculated hydrogen gas, such as automatic or manually controlled pulp and regulators in lines 10 and 12.

The molar ratio of hydrogen gas can be adjusted. The liquid product or effluent of the reaction leaving the hydrogen gas separation unit 3 passes via liquid product line 15 to a means for azeotropic distillation or removal column 5 of the reactor effluent. From the top of the removal column 5', ethers, aldehydes and low molecular weight particles are removed from the top of the removal column 5'.
lights ) J is circulated from the pipe line 14 to the supply tank 71 . The anhydrous alkanol is removed from the lower part of the removal column 5 and is transported back to the feed line 10 via line 15. The purge line 22 contains [heavies]
Alternatively, certain by-products of higher molecular weight may be removed from the system and sent to line 18.

From the middle part of the removal column 5 the alkanol, water and alkanoate ester azeotrope are removed via line 16 and conveyed to means for collecting the effluent or to a water decanter 6. Make-up water can be supplied to the water decanter via the make-up water supply line 17 from a make-up water supply source 7 connected to the line 16 via the make-up water line 17 . Pipe 18 from water decanter
The aqueous layer was extracted by K and an organic recovery column (not shown)
lead.

The upper layer from water decanter 6 consists of concentrated alkanoate ester. Typically, this effluent contains 9 esters.
5X or higher, about 5X alkanol, about 2X water
or less. Asahi transports this mixture to the alkanol separation column 8 via a pipe 19. The purified water-saving ester is withdrawn from the column via line 20 and transported to a storage vessel or recycled to feed line 10 (not shown). The mixture of alkanol, water and percaate ester azeotrope is circulated back to line 16 via line 21 for further separation.

The invention will be further understood from the following examples. Abbreviations used in the data and description of these examples are as follows.

Abbreviation Definition AcH Acetaldehyde AcOH Acetate Acet Acetone BuA1 Butyraldehyde BuOH
Butanol °C degree Celsius CC cubic centimeter CuFt cubic footEff
Efficiency Et20 Ether EtOAc Ethyl acetate ester EtOH Ethanol H20 Water Hr Time IBuOH Isobutanol LH8V Liquid Hourly space velocity m1sc
Other PrOH properties psia pounds per square inch absolute ps ig pounds per square inch gauge temp temperature Yr year % percent # pounds Experimental Procedures The apparatus and procedures for carrying out the following experiments are further understood with reference to FIG. . In the apparatus shown in FIG. 2, a gaseous alkanol is brought into contact with a copper chromite catalyst in a reactor to cause a reaction. Equipment for further purification by azeotropic distillation of the reactant products is not shown in this figure. The apparatus represented in FIG. 2 is suitable for carrying out the method of the invention on a pilot plant scale.

The apparatus illustrated in FIG. 2 used to carry out the method of the invention includes a reactor 30. The apparatus illustrated in FIG. The reactor 30 has an inner diameter of 1 inch (2,5 cIrL) and a length of 48 inches (122 cIIrL).
It has a heating tube of Dowtherm' (Do
wtherm) Apply lining with jacket.

Inside the reactor 30, there is a chamber for housing the glass beads.
□Thermal section 51, catalyst bed 32, and glass beads housing
There is a support portion 33 that is □. The nitrogen cylinder 35 and the hydrogen gas cylinder 36 supply their respective gases through a gas supply pipe 37. Associated devices can be attached to this gas supply line, such as rotometers 25a and 25b, metering pulps 26a and 26b, check pulps 27a and 27b. These rotometers and pulps aid in reaction operation and safety and are a means of controlling the feed molar ratio of hydrogen gas to alkanol feed solution within the reactor. Elephant and hydrogen gas are gas supply pipes
After passing through a passage 37 and passing a pressure gauge 38, it enters a reactor 30.

40 raw material tanks of 4-5 gallons (15-19 liters)
feeds the alkanol feed solution through feed line 41. The feed solution is passed from feed line 41 to feed line 42 by pump 43 . A heating tape is wrapped around the supply line 42. Tank 40 and heated supply line 42 provide a source of gaseous primary alkanol feed solution to reactor 60 . The circulating alkanol is cooled and collected in a feed tank 44 and fed back to the system through a water-cooled jacketed feed line 45. The contents of supply line 45 enter supply line 41 . The alkanol from supply line 42 is transferred to reactor 30
and comes into contact with hydrogen gas from gas supply line 37. The alkanol feed solution and hydrogen gas are contacted with the catalyst bed 32. The alkanol ester and other reaction products also exit reactor 30 via outlet line 50. Outlet pipe 5
0 has a reactor pressure gauge 51 and a pressure regulator 52. The reaction product passes through a water-cooled condenser 53 and the product receiver is collected in a tank 54. The product is further passed through a vented ice trap 55 and an unvented ice trap 56. The condensed product is collected and the hydrogen gas is passed through line 57 to pressure lap 58.

An emergency shutdown system is provided by shutdown means 60 for controlling the reactor barrier 65 and shutdown means 61 for controlling the feed pump and monitoring the temperature of the product condenser. Other gauges, regulators, pulp, and related equipment, such as those shown in FIG. 2, may be incorporated into the conversion unit and are within the skill of those skilled in the art.

The numbered examples are examples illustrating the invention. Examples with letters are for comparison.

Example 1 This example demonstrates the effect of hydrogen gas on the reaction of converting ethanol to ethyl acetate using the apparatus and procedure described above. Vapor phase ethanol is converted into bar show/Cu
-o 203 Contact with chromite steel catalyst 1808C. The results in Table 1 were obtained after continuous operation and regeneration of the catalyst for over 1000 hours. Table 1 shows the results of adjusting the molar ratio of hydrogen gas to alcohol raw material.

Table 1 Effect of adjusting hydrogen gas on the reaction of ethanol to ethanoate 1. 8. 4 Q, 1 (S 2.8
24.6 B6.6. 8 α43
2.8 27.6 89.6 15 0.
80 t<S 2Z993.6 3.0
160 11 25.295+1 The reaction temperature and pressure to obtain these results are 23
1°C and 60 psig (4.2 kg/cWL2G)
Met.

2LH8V represents the volume of liquid raw material per volume of catalyst/time. Values between about 6 and about 1o are commercially acceptable.

A total of 1% product of 3 acetaldehydes is considered commercially acceptable.

4 Efficiency percent is alkanol ester weight: □ Volume percent vs. weight bar of total reaction products including water 1
Cent ratio.

The results of this example demonstrate that controlling the molar ratio of hydrogen gas to alcohol feed with respect to hydrogen gas feed rate, reaction temperature, and reactor pressure is necessary to keep the intermediate aldehyde concentration low throughout the reaction zone. Indicates a certain point. The mole of hydrogen gas per hour is 0.6LH8V
□, the total aldehyde product was reduced by about 1X.

At 1X acetaldehyde, the concentration in the production of ethyl acetate ester gives commercially acceptable results with a corresponding reduction in condensation products of ethyl acetate and other acetaldehydes of at least 95% efficiency.

In this example, the hydrogen gas at 0.8 mol/hour was determined so that the molar ratio of hydrogen gas to ethanol feed solution was α43.
: Indicates that it is 1. 10 moles/hour of hydrogen gas represents a ratio of moles of hydrogen gas to moles of ethanol of 16:1, respectively. □' Example 2 This example demonstrates the effect of water in the alkanol feed solution. In this example, ethanol is converted to ethyl acetate using the same procedure used in Example 1. This example shows that the productivity of converting ethanol to ethyl acetate depends on the water content of the feed solution. The results of this example are presented in Table 2.

Table 2 Effect of water in raw materials0. 04 26.3 9511
．． 07 17.3 92.75. 11
18 92.55. 17 9.4.
92.81 In this example, LI (SVo, 6, temperature 231 °C, pressure 60 psig (4,2'Q /c
m2G), and hydrogen gas is 1.5 mol/hour,
Alternatively, hydrogen gas was maintained at α8 moles per mole of alcohol raw material.

The example results show that the water content in the ethanol feed solution directly affects the weight percent of ethyl acetate production. Increasing the amount of water in the ethanol feed solution thereby reduces the conversion of ethanol to the desired product.

Note that between this example and Example 1, the ester production efficiency is correlated to the feed molar ratio of hydrogen gas to alcohol feedstock.

Example 3 In this example, ethanol is converted to ethyl acetate using the same procedure used in Example 1. This example shows the effects of water in the feed solution and high reaction temperature. Example 2
The decrease in productivity of ethanol conversion to ethyl acetate shown in can be partially compensated for by increasing the reaction temperature. In addition, this example contemplates the productivity that can be expected implementing the method of the invention on an industrial scale. The results of this example are shown in Table 3.

This example shows that the method of the present invention is an inexpensive aqueous ethanol (190%
proofs) can be effectively utilized to achieve commercially desirable efficiency percentages. Commercial results based on this productivity and use of a standard converter for one year are also presented.

Note that between this example and Example 1, the ester production efficiency is correlated to the feed molar ratio of hydrogen gas to alcohol feedstock.

Example 4 This example demonstrates the selectivity of the process of the invention for the conversion of ethanol to ethyl acetate. In this example, ethanol is converted to ethyl acetate using the same procedure used in Example 1. In this example, a 1/8 inch (A2m) bar, CLl-0203 catalyst 180 (2C of about 900mm) is used.
Used after 1400 and 1500 hours of operation, respectively, the reaction products of Table 4.5.6 are obtained. The products in Tables 4 and 5 were obtained using a 200 proof ethanol feed solution.

The products in Table 6 were obtained using a 190 proof ethanol feed solution. Analysis of the reaction products is presented in Tables 4-6.

Table 4 Ethyl acetate 42.3 82.8 Acetic acid, 5 1.0 Acetaldehyde 526.3 Butanol + Butanal 4.0 7
．． 8 ethyl ether, 9t8 acetate), 2. 3511
100, %' Kaoru LH8V to obtain these products is 51 hours -
1. Reaction temperature is 260℃, reaction pressure is 60psig
(4,2#/cn?G). The results in this table were obtained without supplying hydrogen gas to the reactor. Water produced during the reaction was not considered as a product in the calculation of ester selectivity.

Table 5 Ethyl acetate 25.16 96.0
Acetic acid, 03 butanol + butanal, 58 ethyl ether
, 05 Wed , 402622
% "L)IsV to obtain these products is 625 h-1, reaction temperature is 232 °C, reaction pressure is 60 psig
(a, 2 key meeting 2G), and hydrogen gas was supplied to the reactor at a rate of 72 standard liters/hour, or 164 moles of hydrogen gas per mole of ethanol raw material.

“The result of the conversion is about 1
Excluding % acetaldehyde.

Table 6 Ethyl acetate 9419υ Acetic acid, 17 Butanol + Butanal, 38 Ethyl ether, 12 Water, 121Q, 20
% LH3V to obtain these products is 64 hours-
1. The reaction temperature was 251°C, and the reaction pressure was 61 psig (4
, 5 kg/1ya2G) and hydrogen gas was fed to the reactor at 41 standard liters/hour.

The result of 0 conversion was approximately 1%, which was recycled for further reaction.
Exclude 5% acetaldehyde.

This example illustrates the secondary reaction products and concentrations obtained from the process of the invention. The resulting acetaldehyde can be circulated at lower temperatures to achieve lower conversion and better selectivity to ethyl acetate.

This example shows the highest feed molar ratio of hydrogen gas to alcohol feedstock.

This example shows the highest efficiency of ester production of Examples 1-4.

Example A This example demonstrates the conversion of ethanol to ethyl acetate without increased hydrogen gas in the feed to the reactor. The procedure for this example was the same as in Example 1', except that a smaller catalyst screening reactor was used. The reactor is 1/8 inch □(3,2W)X/
It contained 20 CC of 8 inch Calcicat E-18TU copper chromite catalyst. In this example, 12 liters/hour of nitrogen gas was supplied to the reactor. Analysis of the reaction products is presented in Tables 7 and 8.

Table 7 Ethyl acetate 14.9 6B,6 acetaldehyde 4.2 19.4 Butanol + Butanal 2,6 12.021
．． 7 100.0 “LH8V to obtain these products is 10 h−1
, the reaction temperature was 221°C, and the reaction pressure was 51 psig (3
, 6 kg/(cm2G). The water produced in the reaction was not considered as a product in the calculation of ester selectivity.

Table 8 Ethyl acetate 14.4 514 Vinegar
Acid α20.7 Acetaldehyde 8.5 30.4 Butanal 4.8 17.1 Acetone
α10.4 28.0 100.0 ”LH8V to obtain these products is 1iF at 1o
', reaction temperature was 249°C, reaction pressure was 50 psig (
s 5 kil/crt? G). The material balance was:

This example, compared to Example 4, shows that lower ester production efficiencies are obtained when the molar ratio of hydrogen gas to ethanol in the reactor is not adjusted.

Example B and their examples demonstrate that alkanols different from ethanol can be converted to the corresponding alkanoate esters with copper chromite catalysts. The procedure for these examples was the same as for Example A. In these examples, the molar ratio of hydrogen gas to alkanol feed solution was not adjusted. Analysis of the reaction products of Examples B and C are in Tables 9 and 1o, respectively.

Table 9 Propyl propionate 5.7
26.0 Propanal 12.3 56.
22-methylpentanal 1.5
6.92-Methylpentanol 19
8.7 Unknown sample Q, 5 2.
2.

219 100.0 “LH8V to obtain these products is 10:11F
', reaction temperature is 247℃, reaction pressure +! 50 psig
'(3.5 kg/ctrt'G). Assuming cycling of the propatool, the calculated propylpropionate selectivity is 594X.

Table 10 Butylbutanol 16 244 Butanal 143 65.22-Ethylhexanal Q, 52.02-Ethylhexanol 10 4.0 Unknown sample
CL6 2.425.0 1
00.0 LH8V to obtain these products is 10 h-1,
The reaction temperature was 247°C, and the reaction pressure was 50 psig (15
kg/cm2G) and ivy.

These examples demonstrate the ability of steel-containing catalysts to convert primary alkanols to their corresponding esters.

Example 5 This example demonstrates the increased efficiency and productivity of the conversion of ethanol to ethyl acetate □ using the Vershaw Cu-0203 catalyst in operation from shortly after the start of the reaction to about 750 hours of catalyst operation. □In this example,
Ethanol is converted to ethyl acetate by the same procedure used in Example 1. Samples 1 to 9 are test results when the molar ratio of hydrogen gas to ethanol in the reactor is not adjusted, and are for comparison with samples 10 to 18. These are the test results in which the molar ratio of hydrogen gas to ethanol in the reactor was adjusted at various flow rates, reactor temperatures, and reactor pressures.The test conditions and results of this experiment are shown in Table 1.
It is 1.

This example shows the results of continuous operation of the process of the invention using a copper chromite catalyst. A comparison of Samples 10 and 12 shows that lowering the reactor temperature with constant hydrogen gas flow rate and reactor pressure increases the efficiency of ester production and decreases the yield. A comparison of samples 10 and 11 and samples 12 and 13 shows that increasing the reaction value and direct pressure at about 250°C and about 230°C, respectively, increases the efficiency of ester production and the total ester produced. .

Comparing samples 15 and 16, the reactor pressure was 75 psi.
g (5.3 kg/ctl G) This shows that by increasing the FC, the ester production efficiency becomes relatively constant and the total ester produced decreases. Sample 16.1
A comparison of 7 and 18 shows that increasing the hydrogen gas feed rate at constant reactor temperature and pressure increases ester efficiency.

Example 6 This example demonstrates the nine conversion of imbutyl isobutyrate ester using hydrogen gas in the feed to the reactor. In this example, 1/8 inch (3.2 mm
)
The alkanols are converted to alkanoate esters by the same procedure used in Example 1, except that 180 cc of catalyst loaded with oxidized steel of 180 cc are used to obtain the reaction product. Analysis of the reaction products is in Table 12.

Table 12 Inbutyl isobutyrate 5,5 3
7.7 Wednesday 2.1
14.4 Isobutyraldehyde 3.
4 23.3 Light content 3.6
24.6” LH8V to obtain these products
is 10 o'clock, '14.6 100.0 time -1, reaction temperature is 250 °C, reaction pressure is 60 psi
g 1, (4.2 kg / (cm2G),
In addition, hydrogen gas was supplied at a rate of ZO mol/hour to the reaction value.

The calculation of % efficiency assumes that the product is 1. [Although the alumina support caused significant dehydration of K, isobutanol as evidenced by the production of water and heavy fractions, , few, if any, aldehyde condensation products were formed. This example shows that copper-containing catalysts, different from copper chromite catalysts, work according to the process of the invention.

For example, this example shows that the productivity of ethyl acetate in ethanol conversion is increased when acetaldehyde is used to replace a portion of the ethanol feed solution. In this example,
5/16 inch (4,8mm) x 3/32 inch (2
The ethanolic ethyl acetate) Ic conversion was carried out by the same procedure used in Example 1, except that a United Catalyst Twin Incorporated G-66B copper oxide/zinc oxide catalyst 180 eC of 180C, 40) was used. The test conditions and results of this example are in Table 131C.

After about a week of operation, the tubular reactor became clogged with white solids. Analysis of this white solid revealed it to be zinc acetate. Zinc acetate is probably formed by the reaction of acetic acid, a by-product, with zinc oxide in the catalyst. This is exacerbated when using 190 proof ethanol as the feed solution.

This is because increased water content of the feed solution causes increased acetic acid production.

This example shows that increasing acetaldehyde concentration with this catalyst system leads to increased ethyl acetate production.

Example 7 This example demonstrates the very low productivity of ethyl acetate ester in a system using a copper chromite catalyst and removing hydrogen gas from the reaction zone. Hydrogen gas is removed or controlled within the reaction zone to replace some ethanolic acetaldehyde in the feed solution. In this example, ethanol is converted to ethyl acetate using the same procedure used in Example 1.

1/8 inch (3,2cm) x 1/a inch bar show CLI-0203 copper chromite catalyst 18
is used in this reaction. The test conditions and results for this experiment are in Table 14.

Comparison of the results of this example and the results of Example B shows that the zinc-containing catalyst has increased production of ester and increases the concentration of aldehyde in the reaction zone. Increased concentrations of aldehydes within the copper chromite reaction zone reduce ester production. These examples suggest that their reaction routes to ester production are different.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an alkanol conversion unit including means for azeotropically distilling the reactor effluent suitable for use on an industrial scale in the process of the present invention. FIG. 2 is a schematic representation of a continuous ester production unit suitable for producing esters from alkanols on a pilot plant scale without means for azeotropic distillation of the reactor effluent. 1.40, 44: Supply tank 2.30: Reaction device 3: Separation device 4: Collector 5: Removal column 6: Decanter 8: Separation column 35.315 Nigas cylinder 54: Tank 55.515 Nii strap 58: Pressure Procedures subject to trap amendment M double book (method) % formula % Display of case 1985 Patent Application No. 105070 Person making amendment

Claims (1)

[Claims] 1. (a) bringing a gaseous primary alkanol into contact with a copper-containing catalyst in a reactor; (b) adjusting the molar ratio of hydrogen gas to the primary alkanol in the reactor; and said molar ratio is sufficiently adjusted by means of controlling the reaction equilibrium between said primary alkanol and said aldehyde intermediate compound, thereby partially suppressing the formation of said aldehyde intermediate compound and reducing said aldehyde intermediate compound. A method of producing an alkanoate ester comprising increasing the selectivity of a compound to an alkanoate ester reaction product. 2. The method of claim 1, wherein said feed molar ratio of said hydrogen gas to said first alkanol in said reactor is from about 0.05:1 to about 10:1, respectively. 3. The feed molar ratio of the hydrogen gas to the first alkanol in the reactor is about 0.6:1 to about 3, respectively.
:1. 4. A claim in which the molar ratio of hydrogen gas to primary alkanol in the reactor is adjusted by controlling at least one of the amount of hydrogen gas supplied, the reactor temperature, and the reactor pressure. The method described in paragraph 1. 5. The method of claim 4, wherein the first alkanol is brought into contact with the copper-containing catalyst to produce the hydrogen gas, and the hydrogen gas is recycled to the reactor. 6. The method according to claim 1, wherein the first alkanol is ethanol, and the ethanol is a member selected from the group consisting of anhydrous ethanol and aqueous ethanol. 7. The method of claim 4, wherein the reactor temperature is about 200<0>C to about 300<0>C. 8. The method of claim 7, wherein the reactor temperature is about 220<0>C to about 260<0>C. 9. The reactor pressure is about 0 to about 500 psig (about 0
~35 kg/cm^2G). 10. The method of claim 9, wherein the reactor pressure is about 50 to about 80 psig. 11. (a) contacting a gaseous primary alkanol with a copper chromite-containing catalyst in a reactor; (b) adjusting the molar ratio of hydrogen gas to the primary alkanol supplied in the reactor; The feed molar ratio is sufficiently adjusted to control the reaction equilibrium between the primary alkanol and the aldehyde intermediate compound, thereby partially suppressing the formation of the aldehyde intermediate compound and reducing the amount of the aldehyde intermediate compound. increasing selectivity for the alkanoate ester reaction product; (c) collecting an effluent containing the reaction product from the reactor; and (d) separating the alkanoate ester reaction product from the effluent by azeotropic distillation. A method for producing an alkanoate ester, comprising: 12. Claim 11 further comprising: (e) separating said first alkanol from said effluent by azeotropic distillation; and (f) recycling said separated first alkanol to said reactor. the method of. 13. The feed molar ratio of the hydrogen gas to the first alkanol in the reactor is about 0.05:1 to about 1, respectively.
12. The method of claim 11, wherein the ratio is about 10:1. 14. The method of claim 15, wherein said feed molar ratio of said hydrogen gas to said first alkanol in said reactor is from about 0.6:1 to about 3:1, respectively. 15. A claim in which the molar ratio of hydrogen gas to primary alkanol in the reactor is adjusted by controlling at least one of hydrogen gas supply amount, reactor temperature, and reactor pressure. The method according to paragraph 11. 16. The method of claim 15, wherein the first alkanol is brought into contact with the copper chromite-containing catalyst to produce the hydrogen gas, and the hydrogen gas is recycled to the reactor. 17. The method of claim 11, wherein said first alkanol is ethanol, and said ethanol is a member selected from the group consisting of anhydrous ethanol and aqueous ethanol. 18. The method of claim 15, wherein the reactor temperature is from about 200<0>C to about 300<0>C. 19. The method of claim 18, wherein the reactor temperature is from about 220<0>C to about 260<0>C. 20. Claim 1, wherein the reactor pressure is about 0 to about 500 psig (about 0 to 35 kg/cm^2G)
The method described in Section 5. 21. The method of claim 20, wherein the reactor pressure is about 30 to about 80 psig. 22. (a) contacting a gaseous ethanol feed solution with copper chromite in a reactor to produce hydrogen gas; and (b) selectively circulating the hydrogen gas produced in the reactor. adjusting the feed molar ratio of the hydrogen gas to the ethanol feed solution to the reactor, sufficiently controlling the feed molar ratio in the reactor to control the reaction equilibrium between ethanol and the acetaldehyde intermediate compound; (c) removing the ethyl acetate reaction product, ethanol, and water from the reactor; (d) separating the ethyl acetate reaction product and the ethanol from the effluent by azeotropic distillation and recycling the ethanol to the ethanol feed solution. . 23. The feed molar ratio of the hydrogen gas to the ethanol in the reactor is about 0.05:1 to about 10, respectively.
The method according to claim 22, wherein: 1. 24. The raw material molar ratio of the hydrogen gas to the ethanol in the reactor is about 0.6:1 to about 3:1, respectively.
24. The method according to claim 23. 25. Claim 22, wherein the molar ratio of hydrogen gas to ethanol in the reactor is adjusted by controlling at least one of the amount of hydrogen gas supplied, the reactor temperature, and the reactor pressure. The method described in section. 26. The method of claim 22, wherein said ethanol feed solution is a member selected from the group consisting of an anhydrous ethanol feed solution and an aqueous ethanol feed solution. 27. The method of claim 25, wherein the reactor temperature is from about 200<0>C to about 300<0>C. 28. The method of claim 27, wherein the reactor temperature is from about 220<0>C to about 260<0>C. 29. Claim 2, wherein the reactor pressure is about 0 to about 500 psig (about 0 to 35 kg/cm^2G).
The method described in Section 5. 30. The method of claim 29, wherein the reactor pressure is about 30 to about 80 psig (about 2.1 to 5.6 kg/(cm^2G)). 31. a source of a phased primary alkanol and a copper chromite-containing catalyst; (b) means for adjusting the molar ratio of hydrogen gas to the primary alkanol in the reactor; to control the reaction equilibrium between the primary alkanol and the aldehyde intermediate compound, thereby partially inhibiting the formation of the aldehyde intermediate compound and alkanoate ester reaction products of the aldehyde intermediate compound. (c) means for collecting an effluent containing the reaction product from the reactor; and (d) azeotropically separating the alkanoate ester reaction product from the effluent. 32. An apparatus for producing an alkanoate ester, further comprising: (e) means for circulating said separated first alkanol solution from said azeotropic distillation effluent to said reactor. 33. The apparatus of claim 33, wherein said means for adjusting the feed molar ratio of hydrogen gas to said first alkanol within said reactor comprises means for circulating hydrogen gas produced within said reactor. Apparatus described in section.